Air drying apparatus



June 22, 1943. c. THU MIM ETAL 2,322,603

AIR DRYING APPARATUS Filed Jan. 16, 1941 7 III u Out 0 m w w em A f fr m c a a C. h

Patented June 22, 1943 2,322,893 AIBDRYING APPARATUS Carl Thnmim, Yeadon, and Percy Bartlett,

Springfield, Pa., asaignors to General Electric Company. a corporation of New York Application January 16, 1941, Serial No. 374,792

9 Claims.

terial such as potassium or sodium hydrochloride 0'' silica gel. When hygroscopic material is employed, it is commonly arranged in a container placed in the air line carrying the compressed air from its source to a storage tank or other apparatus where it is to be used. These containers are arranged so that the material is contained in a cartridge, and so that the container may be opened readily for the replacement of the cartridge. These arrangements are somewhat undesirable because of the necessity of opening the compressed air system which requires that the operation of the compressor be stopped and the pressure removed.

It is an object of our invention to provide a simple and easily constructed apparatus for drying air or gas by employing dehydrating material and an improved arrangement for reconditioning or reactivating the material which does not require reduction of the pressure of the system and the-opening of the system.

Another object of our invention is to provide an air or gas drying apparatus and an improved arrangement for automatically maintaining the water absorbing properties of the hygroscopic material.

Further objects and advantages of our invention will become apparent as the following description proceeds, and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of our invention reference may be had to the accompanying drawing in which Fig. 1 illustrates somewhat diagrammatically an air compressing apparatus embodying our invention and arranged to supply compressed air for operation of an electrical circuit breaker; Fig. 2is an enlarged sectional view of a portion of the apparatus shown in Fig. 1; and Fig. 3 is a sectional view of a compressed air tank or storage container provided with a modified form of a drying apparatus embodying ourinvention.

In general the drying apparatus shown in the drawing comprises an air pressure tank supplied with air from a suitable compressor and provided with a suitable receptacle in which is arranged a mass of hydroscopic material maintained in direct contact with air within the tank so that it is available to treat the air and remove moisture therefrom. The outlet of the tank is connected to an electrical switching mechanism or other apparatus utilizingthe dried air. In order to reactivate the moisture absorbing material, a heating coil is provided to heat the mass of material and suitable valves are arranged so that during the heating operation moisture driven from the material is discharged to the atmosphere outside the compressed air system. Compressed air from the tank suitably throttled may be used to assist in the discharge of moisture from the system.

Referring now to the drawing, the apparatus illustrated in Fig. 1 comprises an air'compressor Ill driven by an electric motor II and having an intake l2 and a discharge connection l3. The compressed gas discharged from the compressor passes through the connection l3 into a suitable separator ll where oil and other foreign matter is removed from the air which then passes through a connection I5 to a storage tank i6. Suitable valves l1 and I8 are provided on either side of the separator H to isolate it from the system for inspection and repairs. The compressed air in the tank it which is dried by a suitable drying agent arranged in a dryer i9 is discharged from the tank i6 through a connection 20 and enters an auxiliary storage tank 2|, a suitable valve 22 being provided in the connection 20 to shut ofl' communication between the tanks i6 and 2| when desired. The dried compressed air in the tank 2i is arranged to be discharged through a connection 23 to extinguish an are within a structure 24 when the switch is opened. A suitable quick opening outlet valve 25 actuated by a plunger 261s provided to release the air from the tank 2i when desired and to cooperate with the compressor valves to retain air under pressure in the tanks l6 and 2| when the valve 25 is closed. The control mechanism whereby the valve 26 is operated in response to the opening of the circuit breaker has not been shown as it forms no part of the present invention. The circuit breaker comprises an insulated casing 21 within which are mounted a stationary electrical contact 28 and a movable contact 29:

' ceptacle 32 which is arranged to communicate with the interior of tank I through a gate valve 33 by which it is connected directly to the tank, the gate valve providing the desired wide opening between the tank and the receptacle so that a considerable area of moisture absorbing material is' exposed to the air in the tank. The details of the construction of the receptacle 32 are clearly shown in Fig. 2. The receptacle is provided with a flange 34 for securing it to a corresponding flange on the gate valve 33, and within the receptacleis arranged a wire mesh basket or container 35 which supports a mass of hygroscopic material 38. At the bottom of the container 35 is an outlet opening 31 arranged to communicate with the outsid atmosphere through a stop cook or bleed-off valve 38. Inorder .to heat the container 32 and thereby heat and reactivate the hygroscopic material 36, we provide a heating coil 39 surrounding the receptacle 32 and in contact therewithc i The heating coil may be energized by connecting to power supply lines by means of a manually operable switch 4i.

When it is desired. to reactivate the material 36 after it has absorbed sufficient water to reduce its water absorbing capacity materially, the

gate valve 331s closed to separate the container 32 from the tank l6 and the valve 38 is opened. Theswitch 4| is then closed to heat the container 32 and the-moisture driven from the material by theheat is discharged to the outside through't'he-stop. cock 38. It may be desirable to tank l6. .However, it may be. desirable to close the valve 22 't'rprevent moisture containing compressed air from passing to the tank 2i. As soon as the material 36 has been reactivated, the switch 4| is opened to deenergizethe heater 39 and the stop cock 331s closed and the gate valve 33 is opened. Thereactivated material is then available for removing the moisture from the tank l6.

In Fig. 3 we have shown an arrangement which provides for automatic reactivation of the hy-. groscopic material. The device shown in Fig. 3 may be connected in the air circuit shown in Fig. 1 and the inletand outlet connections provided forthis purpose have been indicated by p the same numerals'as in Fig. 1. In Fig. 3 a compressed air tank 42 is'provided with a flanged opening 43 on itsupper-sideand within thisv opening is supported a receptacle 44 containing a mass-of hygroscopic material 45. The lower .portion of the container 44' is of reduced cross is mounted on the flange 49 about the opening 43 of the tank and a cover plate 50 is bolted to the flange 43 by a plurality of bolts 5! which securely clamp the flange 48 into position, suitable gaskets 52 being provided to seal the joints between the flanges. It will be evident that the container 44 is arranged so that air discharged from the tank 42 passes through the material 45 and thence through a discharge connection 53 and a valve 54 to the outlet connection-20 through a passage 54a in a plunger 54b vof the valve. The air is thus dried by the y roscopic material upon discharge from the tank 42. In order to reactivate the material 45 we provide a heating coil 55 surrounding the reduced portion 48 of the container 44. The heater is arranged to be energized from supply lines 53 through a switch 51. A detachable electric plug connection 58 is provided so that the cover 54 may be removed readily without interfering with any permanent connections to the heater, the plug 58 being provided with a socket member 59 mounted on the cover 50. In order to provide automatic reactivation of the material 45 after it has absorbed suflicient water to reduce materially its water absorbing capacity, we provide a moisture sensitive device 60 arranged in a chamber 61 formed in the cover plate 50. The device 80 may be any suitable moisture sensitive element or humidostat which is arranged to activate a switch 52 whenever the relative humidity or moisture content of the air discharged from the receptacle 44 and passing through the chamber 8| rises above a predetermined value. When the switch 62 is operated, it connects a solenoid 63 across the lines 53 and the solenoid draws an armature 54 to the right against the force of the spring 35 and moves the plunger 54b tocperate the valve 54 and shut off the communication between the connection 53 and the outlet connection 20, and to connect the tank 42 in communication with the atmosphere outside the tank through an orifice or throttling opening 68 in the casing of the valve 54. The air to be bled-ofi and discharged from the orifice 65 flows from the connection through a recess 81 in the plunger 54b. When the plunger 54b has been moved to the right between solenoid 53 and has cut oil communication between the connections 53 and 20, it closes the switch 51 thereby energizing the heater 55 and heating The spring 55 then returns the plunger 54b to its left hand position opening the switch 51 and.

deenergizingthe heater and shutting ofl' the passage of air to the orifice 66; this places the connections- 53 and 25 again in communication throughthe passage 54a of the valve 54. The apparatus shown in Fig. '3, therefore, operates automatically to maintain thehygroscopic material in an activated condition and toprevent the discharge of air from the tank 42 to its outlet connection 20 during the reactivating period; v

It will readily be apparent from the foregoing that we have provided a drying apparatus of the type using hygroscopic material and which is of simple construction and does not require the stoppingof the operation of the compressor or the opening of the system in order to reactivate the hygroscopic material.

While we have described our invention in connection with a compressed air system for sup plying air to an electrical switching apparatus,

other applications will readily be apparent to those skilled in the art. We do not, therefore, desire our invention to be limited to the particular constructions shown and described and we intend in the appended claims to cover all modiflcations within the spirit and scope of our invention.

What we claim as new and desire to secure by letters Patent of the United States is:

1. An apparatus for removing moisture from a gas comprising a closed tank adapted to store a gas under pressure and having an inlet for admitting gas thereto and an outlet for discharging gas therefrom and valves for retaining gas under pressure in said tank, a removable container secured directly to said tank and arranged in communication therewith, said container being arranged to hold a mass of hygroscopic material and present a substantial area of said material in direct contact with gas in said tank for removing moisture from the gas in said tank, a heater for heating the material in said container for driving moisture therefrom to recondition the material, and means including a discharge connection for bleeding air from said tank through said container during operation of said heater to discharge to the outside moisture removed from the hygroscopic material.

2. An apparatus for removing moisture from a gas comprising a closed tank adapted to store a gas under pressure and having an inlet for admitting gas thereto and an outlet for discharging gas therefrom and valves for retaining gas under pressure in said tank, a removable container secured directly to said tank and arranged in communication therewith, said container being arranged to hold a mass of hygroscopic material and present a substantial area of said material in direct contact with gas in said tank for removing moisture from the gas in said tank, a

' heater for heating the material in said container gas comprising a closed tank adapted to store a gas under pressure and having an inlet for admitting gas thereto and an outlet for discharging gas therefrom and valves for retaining gas under pressure in said tank, a container in communication with said tank and said outlet, a mass of hygroscopic material arranged in said container and in direct contact with gas in said tank for removing moisture from gas passing from said tank to said outlet, a heater arranged to heat said material in said container for driving moisture therefrom to recondition said material, a bleed-off valve arranged in communication with said outlet between said container and said outlet valve for discharging gas to the atmosphere outside said tank, means dependent upon a predetermined high relative humidity of the gas discharged from said tank for energizing said heater, said means being operable to energize said heater only when said valve in said outlet is closed and said bleed-off valve is open.

4. An apparatus for removing moisture from a gascomprising a closed tank adapted to store a gas under pressure and having an inlet for admitting gas thereto and an outlet for discharging gas therefrom and valves for retaining gas under pressure in said tank, means including a container arranged to hold a mass of hygroscopic material therein and presenting a substantial area of said material in direct contact with the gas in said tank for removing moisture from gas passing from said tank tosaid outlet, means including a discharge connection between said outlet and said container for discharging gas to the atmosphere outside said tank, means for closing said outlet and opening said discharge connection, a heater arranged to heat the material in said container for driving moisture therefrom to recondition the material, and means dependent upon a predetermined high relative humidity of the gas discharged from said tank for actuating said means for closing said outlet and opening said discharge connection and for energizing said heater whereby moisture removed from the material during the reconditioning thereof is discharged to the atmosphere.

5. An apparatus for removing moisture from a gas comprising a closed tank adapted to store a gas under pressure and having an inlet for admitting gas thereto and an outlet for discharging gas therefrom and valves for retaining gas unarranged to heat said material in said container for driving moisture therefrom to recondition said material, means dependent upon a predetermined high relative humidity of the gas flowing to said outlet after passing over said material for actuating said solenoid valves to close said outlet and to open said discharge connection, and means depending upon the actuation of said solenoid valves by said last mentioned means for energizing said heater whereby moisture removed from said material during the reconditioning thereof is discharged'to the atmosphere.

6. An apparatus for removing moisture from a gas comprising a tank adapted to store gas under pressure and having an inlet for admitting gas thereto and an outlet opening through which gas may be discharged therefrom, a receptacle removably secured in said outlet opening and arranged to maintain a mass of hygroscopic material in the path of gas discharged from said tank, means including a cover plate for said receptacle for securing said receptacle in place and for sealing said tank, said cover plate having an outlet for the discharge of ga from said tank, a heater for heating said material in said receptacle, and means including a valve in said outlet connection for closing said outlet and for affording a passage of gas through said hygroscopic material to the atmosphere outside said tank whereby moisture removed from said hygroscopic material by operation of said heater may be discharged to the atmosphere outside said tank.

'7. An apparatus for removing moisture from a gas comprising a tank adapted to store gas under pressure and having an inlet for admitting gas thereto and an outlet opening through which gas may be discharged therefrom, a receptacle removably secured in said outlet opening and arranged to maintain a mass of hygroscopic mate- 'rial in the path ofgas discharged from said tank, means including a cover plate for said receptacle for securing said receptacle in place and for sealing said tank, said cover plate having a chamber formed therein and having an outlet communieating with said chamber for the discharge of gas from said tank, a heater for heating said material in said receptacle, means including a valve in said outlet connection for closing said outlet and for afiording a passage of gas through said hygroscopic material to the atmosphere outside said tank whereby moisture removed from said hygroscopic material by operation of said heater may be discharged to the atmosphere outside said tank, and means including a moisture sensitive element arranged within said chamber 101' operating said valve to close said outlet and for operating said heater whenever the moisture content oi the air within said chamber rises above a predetermined value, said last mentioned means being arranged to restore said apparatus to normal operation upon the decrease of the moisture content of the air in said chamber below a. predetermined value.

8. An apparatus for removing moisture from a gas comprising a tank adapted to store gas'under pressure and having an inlet for admitting gas thereto and an outlet opening through which gas may be discharged therefrom, a receptacle removably secured in said outlet opening and arranged to maintain a mass 01' hygroscopic material in the path of gas discharged from said tank, means including a cover. plate for said receptacle for securing said receptacle in place and for sealing said tank, said cover plate having an outlet for the discharge of gas from said tank, an electric heater for heating said material in said receptacle, a detachable electrical connection for said heater including one member secured to said cover and another member secured to said heater whereby said cover may be removed without interfering with said heater, and means including a valve in said outlet connection for closing said outlet and for affording a passage of gas through said hygroscopic material to the atmosphere outside said tank whereby moisture removed i'rom said hygroscopic material by operation oi said heater may be discharged to the atmosphere outside said tank.

9, An apparatus for removing moisture from a gas comprising a tank adapted to store gas under pressure and having an inlet for admitting gas thereto and an outlet opening through which gas may be discharged therefrom, a receptacle remov'ably secured in said outlet opening and arranged to maintain a mass of hygroscopic material in the path of gas discharged from said tank, means including a cover plate for said receptacle for securing said receptacle in place and for sealing saidtank, said cover plate having an outlet for the discharge of gas from said tank, an electric heater for heating said material in said receptacle, a detachable electrical connection for 4 said heater including one member secured to said cover and another member secured to said heater whereby said cover may be removed without interfering with said heater, means including a valve in said outlet connection for closing said outlet and for affording a passage of gas through said hygroscopic material to the atmosphere outside said tank whereby moisture removed from said hygroscopic material by operation of said heater may be discharged to the atmosphere outside said tank, automatic means mounted on and removable with said cover and including a moisture sensitive element arranged in the path of the air between said receptacle and said outlet for actuating said valve when the moisture content of the gas discharged from said tank is above a predetermined value and for energizing said heater to drive the moisture from said material.

CARL 'I'HUMIM. PERCY BARTLEI'I. 

